Does Birth Order Affect Your Personality?

New research could debunk this popular theory.


Family, Self Help
Siblings playing together.

(Ground Picture / 

Are you the oldest child? The youngest or one of the in-betweens? No matter where you fall in your family you probably think that your birth order affects your personality and your chances for success in life.

This theory has been around for about 100 years, according to National Geographic, but now psychologists and researchers think that it may be time to drop the stereotypes about sibling order and personality.  

Origins of the birth order theory
While there have been some inherent rights to being the oldest child, like better education and inheritances that have existed since ancient times, the psychology theory of birth order was developed in the early 20 th century by psychologist Alfred Adler who claimed that birth order influenced not only social status but also personality traits.

Adler wrote in 1931: “The position in the family leaves an indelible stamp upon the individual’s lifestyle.” He claimed that since the birth of younger siblings deprives the firstborn of their parent’s attention and that this results in the child being more neurotic, more conservative, as well as being an overachiever.

Adler’s theory said that middle born siblings were more competitive and were attention grabbers while the youngest children were pampered and lazy.

The psychologist’s theory became very well-known due to his international lectures and psychology texts, Due to its popularity, much research was conducted to support it. The birth order theory has been associated from educational success to athletic ability and is still supported by many today. But is sibling order actually an accurate prediction of a person’s personality?

New research questions theory
The fact is that the science of personality development is far from settled. Personality studies look at what is called the big five” personality traits. These include openness, conscientiousness, extroversion, agreeableness, and neuroticism.

Recent studies about birth order offer a scientific challenge to Adler’s theory. That’s because this research relies on larger data sets and statistical data than earlier research, reported THE Washington Post in 2019.

One 2015 study that was conducted by Rodica Damian, an associate professor of psychology at the University of Houston, used data from over 440,000 US high school students. After taking in consideration socioeconomic status, sex, and age, Damian wrote that the study found that: “The association between birth order and personality traits is as close to zero as you can get,”

Another study conducted in 2015 by Stefan Schmukle, a psychologist at the University of Leipzig in Germany, had similar conclusions. The researchers assessed 20,000 people in Germany, the US, and the UK and found that birth order did not alter any of the Big Five personality traits.

While the studies did find evidence that firstborns tended to be slightly more intelligent, that is probably due to the fact that firstborns most likely had more mental simulation and attention from parents, it does not mean that the birth order theory is valid.

There is a small effect where firstborns get higher levels of education,” Damian told The Washington Post. “If you only pay for college for the firstborn, or the money runs out by the time the second-born is old enough, then that will influence their life.”

Family dynamics and personality
Birth order doesn’t exist separately outside of family dynamics, according to verywell mind. These include tangible things like genetics, health, family resources, and socioeconomic status. Parenting styles change due to environmental conditions and variables like sibling spacing and gender also have to be taken into consideration.

While there is some truth to the idea that firstborns get more attention, and more responsibility, the fact is that your personality is less influenced by the order of your birth and more by your environment.

But old beliefs are difficult to let go of. In fact, in her study, Damien described the birth order personality theory as a “zombie theory” that continues no matter how much evidence against it is collected. Once an idea is accepted, it is difficult to let it go.

But instead of attributing the willingness to take risks to being a middle child, or your doctorate to being a firstborn, remember your achievements are do to your own hard work, values, and talents and not to your birth order.

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